The transfer of work between the stations of a multi-stationed machine, such as a press for the conversion of can ends, determines to a great degree the speed at which the machine can operate. The problem of work transfer is compounded when the orientation of the workpiece must be controlled throughout the operation.
One type of mechanism which has been employed for the transfer of workpieces in a multi-station machine is the reciprocating slide which is equipped with a series of pockets or cavities to hold the workpiece during its transfer from station to station. The slide is constructed in two segments which are brought together to engage the workpiece and moved apart to release it. Separate sets of guide bars are employed to direct the longitudinal movement of the slides in transferring work between stations and to direct the in and out transverse movement of the slide segments in engaging and releasing the workpieces. The use of multiple sets of guide bars imposes definite limitation on both the speed of transfer and the control of the workpiece.
Alternative structures have been suggested which address the problem of workpiece control by employing gripping members which are spring loaded or otherwise biased to positively engage the workpiece. These structures tend to be complex with many working members, which must be adjusted and maintained, to ensure adequate control without distorting or damaging the workpiece. The complexity and mass of these transfer mechanisms serve to constrain the operating speed of the machine and at the same time add to the problems of maintenance, lubrication and noise. Finally these mechanisms are not readily adaptable to handling changes in workpiece size or shape.
Accordingly it is an object of this invention to provide a rapid transfer mechanism which enables work to be transferred from station to station in a multi-station machine without loss of orientation.
It is also an objective of this invention to provide a transfer mechanism with a minimum of working members which is simple but highly effective.
Finally, it is an objective of this invention to provide a transfer mechanism which is capable of handling a variety of workpieces without damaging the workpiece or introducing unnecessary contamination thereto.
The following patents are considered by the inventor to be material to the examination of the application:
______________________________________ U.S. 3,620,381 McCaughey Nov. 16, 1971 U.S. 3,528,575 McCaughey Sept. 15, 1970 U.S. 3,521,760 Wallis July 28, 1970 U.S. 3,430,782 Hendel March 4, 1969 U.S. 3,397,799 Wallis Aug. 20, 1968 U.S. 3,921,788 Roberson et al Nov. 25, 1975 ______________________________________